Here I can’t sue mr Amash if I disagree with his bill, but I can sue him as a private citizen if he violates my civil rights as a person.
In the case of Federal Legislators, their immunity is written into the constitution explicitly.
No such explicit provision exists for government employees.
Probably depends on exactly where you are, but in the US the "LL" in "LLC" is "Limited Liability". (The same concept applies for a C-corp, and Europe has equivalent constructs AFAIK.)
One of the main selling points of a corporation is limited liability. If you are acting on behalf of the company you are very explicitly not "jointly" or in any other way liable for its actions. There are very specific things you have to do wrong to become individually liable; this is called "piercing the veil":
https://www.nolo.com/legal-encyclopedia/personal-liability-p...